Spyderco Forums

DunninLA wrote: ↑

Wed Mar 29, 2023 10:45 pm

blues wrote: ↑

Wed Mar 29, 2023 4:34 pm

M390 does have better edge retention according to Larrin's chart:

Larrin's chart is not for true "edge retention", though that is the term he uses. It is really for "edge abrasion resistance", since it uses CATRA, and all the CATRA machine tells you is resistance to edge abrasion in the absence of impact. Real edge retention includes the impact of the material the knife hits (usually wood) after it cuts through whatever it's cutting through.

Pete's tests show Magnacut keeps its edge longer than M390, by a lot ... it cuts through the rope (edge retention), and then hits into the wood cutting board (impact resistance), which *combined* tells you about true edge retention. The CATRA machine does not combine the two, so it is of limited value, and misleading to boot.

I will say this though... if you always cut things in the middle of the air, with no impact of the blade on anything after the cut, then CATRA seems like a good measurement. But I sure as **** don't cut things in the middle of the air.

Larrin's chart should have Magnacut at 7, possibly 8, if we're talking real world "edge retention", and not the CATRA "edge abrasion resistance" which is what the column in his chart should be named.

Great point I was wondering how M390 was doing better as it did not in my use.

blues wrote: ↑

Wed Mar 29, 2023 4:34 pm

M390 does have better edge retention according to Larrin's chart:

Open question about the values in the chart.

Toughness and Edge Retention are entangled with each other. If you heat treat for max toughness the edge retention suffers and vice versa.

So are the values shown the Maximum possible values such that you can't have both at the same time ?

For example if your knife's edge retention is 5, do you still have a value of 7 for toughness ?

Or are the values given all for something like 60 HRc ?

I believe the good Dr. Larrin heat treats to an ideal selected for each individual steel represented. Then the steel is tested. The values you see in the chart are where they line up based on the ideal heat treat for each individual steel trying to maximize the particular steel's capabilities. So each are heat treated differently and the results you see are where they line up in testing at that heat treat for that specific steel.

Not to say you are wrong in what you are saying about the relationship. I think to gain one thing another will lose. But that is my understanding of the testing results.

Much more to see at https://knifesteelnerds.com/

JSumm wrote: ↑

Fri Mar 31, 2023 8:10 pm

I believe the good Dr. Larrin heat treats to an ideal selected for each individual steel represented. Then the steel is tested. The values you see in the chart are where they line up based on the ideal heat treat for each individual steel trying to maximize the particular steel's capabilities. So each are heat treated differently and the results you see are where they line up in testing at that heat treat for that specific steel.

Not to say you are wrong in what you are saying about the relationship. I think to gain one thing another will lose. But that is my understanding of the testing results.

Much more to see at https://knifesteelnerds.com/

On a folder (!) for me it is edge retention > toughness, while corrosion resistance is nothing I even consider with any steel I have been trying on a Spyderco so far (including the not great in that regard REX 45, HAP 40, XHP...).

So the good, old S30V is pretty much completely rustproof in "my world" (I would not mind little spots and stains on a blade at all anyway) and so "beats" MC just for me, if I go only by Larrins charts.

Though real world use is something else of course:

For example:

Larrins charts completely show what I felt in my layman use of LC200 N (when it came out some said it would hsve edge retention "like S30V" or at least "between VG10 and S30V", in my use it feels more like holding an edge not even as good as VG10)

While in my use - again, completely unscientific of course - REX 45 seems to "do a lot better" (in all three categories) than it "should" according to the charts.

That said: I do believe MC must be one of the best all aröund steels from what I've read so far!

I'm sure you'll see more K390 in Golden after the expansion is finished. We've had some limited capacity issues of late.

sal

sal wrote: ↑

Sat Apr 01, 2023 1:25 am

I'm sure you'll see more K390 in Golden .....

sal wrote: ↑

Sat Apr 01, 2023 1:25 am

I'm sure you'll see more K390 in Golden after the expansion is finished. We've had some limited capacity issues of late.

sal

And Magnacut too?

sal wrote: ↑

Sat Apr 01, 2023 1:25 am

I'm sure you'll see more K390 in Golden after the expansion is finished. We've had some limited capacity issues of late.

sal

That's exciting. I'd love a K390 Manix or Native... or just about any other knife made in Golden

I'm really looking forward to the expanded capacity/capability from Golden.

DunninLA wrote: ↑

Wed Mar 29, 2023 10:45 pm

blues wrote: ↑

Wed Mar 29, 2023 4:34 pm

M390 does have better edge retention according to Larrin's chart:

Larrin's chart is not for true "edge retention", though that is the term he uses. It is really for "edge abrasion resistance", since it uses CATRA, and all the CATRA machine tells you is resistance to edge abrasion in the absence of impact. Real edge retention includes the impact of the material the knife hits (usually wood) after it cuts through whatever it's cutting through.

Pete's tests show Magnacut keeps its edge longer than M390, by a lot ... it cuts through the rope (edge retention), and then hits into the wood cutting board (impact resistance), which *combined* tells you about true edge retention. The CATRA machine does not combine the two, so it is of limited value, and misleading to boot.

I will say this though... if you always cut things in the middle of the air, with no impact of the blade on anything after the cut, then CATRA seems like a good measurement. But I sure as **** don't cut things in the middle of the air.

Larrin's chart should have Magnacut at 7, possibly 8, if we're talking real world "edge retention", and not the CATRA "edge abrasion resistance" which is what the column in his chart should be named.

I agree that he should call it wear resistance instead of edge retention, but he DOES also talk about "edge stability" a lot on his blog, which is what you're discussing when speaking about how an edge holds up to impacting a cutting board.

However, I have to disagree with your take on this. I seldom ever use a cutting board, or any kind of backing surface. Meanwhile, when I do, it's usually for cooking, and usually a plastic cutting board. That kind of invalidates any testing difference that was caused by a wood cutting board for my uses and that's really the reason why CATRA is used.

It's not a limited test, it's a controlled test. Otherwise if you wanted to devise a "real world" edge retention test that accounted for impact into a backing surface, you'd introduce a medley of other variables to consider. For example in the CATRA test, more acute edges perform better, but with a cutting test that included impact into backing surface it might be the opposite, where a more obtuse edge would be better. The same could be said for the hardness of the edge if chipping were a factor. But even if we're talking about the same geometry, you have to consider how much force the edge is actually impacting with and if the impact load is static or dynamic; in other words, what if a user reduces cutting force near the end of the cut to reduce the force of the impact? That would need to be simulated and accounted for to match "real world" cutting. For that matter, most people don't make perfectly perpendicular cuts with no lateral movement, and end up hitting a backing surface at different angles, and may twist the blade a little upon or after impact. Then at the end of all of that, there's also the myriad of different cutting board materials to consider.

To put that differently... How do I know that Pete didn't use a very heavy hand, a soft blade of M390 and a hard blade of MagnaCut, and a really hard wood cutting board? Then if I used a light hand, a hard M390 blade and a soft MagnaCut blade, and a soft plastic cutting board, would I see better edge retention for M390?

I don't think the CATRA test was ever actually intended to be a predictive test of which steel would cut longer, since in the real world there's so many different variables to consider. But on the other side of that coin is that the only way you can get really definitive data to compare one steel (or edge geometry, or hardness level, etc.) to another is controlling for those various factors. In other words, just because one steel stays sharper longer than another in a specific unlike-application doesn't invalidate the CATRA results. If someone feels mislead by them, then I would say they misused that data.

DunninLA wrote: ↑

Wed Mar 29, 2023 11:08 pm

gooeytek wrote: ↑

Wed Mar 29, 2023 1:47 pm

] the only knife I'll probably have in MC is a custom Santoku I'm having made.

Good choice.

I think kitchen use is actually the ideal place for Magnacut to be the steal (spelling intended) to rule all steels, more than EDCs, where you could argue for a lot of different steels depending on use case. I suppose for protein breakdown type work maybe LC200N would be better with higher toughness.

For the kitchen, MC has the hardness to resist edge rolling when the blade hits the cutting board while chopping. It has the corrosion resistance for when a knife is left wet for hours, or when citrus is cut. It has the toughness to resist the microchipping that is so common with Blue 2 or Super Blue, or any of the paper steels, for accidentally hitting bones, or just from chopping.

My thoughts exactly! :D

I feel like MagnaCut will be the truly stainless complement to CruWear, for those wanting a "best compromise" steel that favors corrosion resistance over sharpening response.

I have yet to sharpen my N5 Salt enough to know if I like it well enough to think about getting duplicate knives in MagnaCut, but it certainly does seem like it could be a fantastic alternative for use in the knives the OP suggested.

Definitely snagging a Manix Salt when they drop though ...after that, I'll wait and see.

awa54 wrote: ↑

Wed Apr 19, 2023 11:37 am

I feel like MagnaCut will be the truly stainless complement to CruWear, for those wanting a "best compromise" steel that favors corrosion resistance over sharpening response.

From what I'm hearing, the reports are very favorable on the sharpening response, as well as the ease of putting an excellent edge on MagnaCut at 63-64 Rc.

I've only honed mine so far on basswood with 1 micron diamond, and bare 'roo leather. Responds quickly there as well.

Every reason to be encouraged, as far as I can tell.

While I will be passing on the Salty N5, I'm eagerly looking forward to Magnacut spreading its wings across the factories so I can get a piece of this pie.

I vote Magnacut them all.

Freediver wrote: ↑

Wed Apr 19, 2023 4:15 pm

I vote Magnacut them all.

Roger that!

awa54 wrote: ↑

Wed Apr 19, 2023 11:37 am

I feel like MagnaCut will be the truly stainless complement to CruWear, for those wanting a "best compromise" steel that favors corrosion resistance over sharpening response.

I have yet to sharpen my N5 Salt enough to know if I like it well enough to think about getting duplicate knives in MagnaCut, but it certainly does seem like it could be a fantastic alternative for use in the knives the OP suggested.

Definitely snagging a Manix Salt when they drop though ...after that, I'll wait and see.

I think it sharpens really well. I tried a high grit edge on it just to see how fine I could take it. The results were impressive, but I got carried away stropping on bare leather and killed the aggression. The last time I stopped at a 650 grit diamond matrix stone and stropped with 1 micron gunny juice on leather. That edge is fantastic; shaved clean, sliced through newsprint and receipt paper with ease, and had plenty of aggression. Deburring isn’t as good as 15V or K390, but that’s getting better with each sharpening, and even the first time it wasn’t worse than S30V. I don’t know about Magnacutting all the knives, but I’d love to see it become the base model steel.

when lc200n came out, there was some buzz about making salt versions of everything with it. i was definitely on board for that. now there's buzz about magnacut being used to make salt versions of everything. that's cool with me too. as it's been said though, i don't necessarily care if every model with magnacut is designated as a salt. i'd be really happy with a standard g10 manix with magnacut and steel liners. salt or not, it would be a great edc knife. same for other models. a delica wharncliffe that's more corrosion resistant than vg10 but that also has liners would be great.

The only thing that keeps me from taking a g10 anything fishing (in either fresh or saltwater where I know I'll be wading) or biking is the stop pin and/or liners. They tend to corrode as easily as s30v. At least, that was my experience a few years ago. I'd be curious to hear if this has changed. A salt version of their g10 models would almost certainly be a buy from me. I love the action of my g10 models. I think magnacut would be a nice upgrade in the corrosion department, but I've been happy with the corrosion resistance of 20cv and s110v. My preference is still a hard tool steel and so far, my magnacut mule basically behaves as a stainless cruwear.

I have several small fixed blades in Magnacut now and my experience with them suggests that it would be perfect as the default steel for pretty much any EDC folder. Very easy to sharpen and edge retention in real world situations is much better than the CATRA numbers would suggest unless you spend your day cutting up gritty old carpets or something.